FIG. 7 is a perspective view showing the structure of a memory module used for memory expansion in a personal computer etc.
In the drawing, the reference character 17 denotes a module substrate, 18 denotes electrodes, and 19 denotes semiconductor devices for use as memory.
When expanding memory in a personal computer, the memory module shown in FIG. 7 is inserted in a memory expansion socket attached to the personal computer.
In the memory module, as shown in FIG. 7, a plurality of semiconductor memory devices are mounted on the module substrate 17 and the electrodes 18 for making external connections are arranged along the edge of the memory module substrate 17.
The electrodes 18 are inserted in a memory expansion socket in the body of the personal computer to make contact with the contact pins in the memory expansion socket, thus making electric connection.
However, with the recent increase in memory capacity of the semiconductor memory devices, it is not always necessary to pack a plurality of semiconductor memory devices 19 in the memory module as shown in FIG. 7.
For the packaging, low-price resin-encapsulation packages are used for the semiconductor memory devices 19.
Typical packages include the TSOP (Tin Small Outline Package) shown in FIG. 8 and SOJ (Small Outline Jleaded Package) shown in FIG. 9, for example.
These packages have gull-wing-like or J-shaped external leads 20 extending along the outer sides of the body so that they can be mounted with solder on a mounting substrate (the module substrate 17, for example).
These packages have the leads extending on the outside of the package body; when the electrodes 18 of the module substrate on which semiconductor memory devices using these packages are mounted as shown in FIG. 7 are inserted in a socket in a personal computer, the external leads 20 may be deformed unless handled carefully enough.
However, since expansion memories for personal computers etc. are for use by common users, they must be so constructed that they can be attached easily without suffering deformation of the external leads even if they are handled somewhat roughly, but the conventional package structures as shown in FIG. 8 and FIG. 9 do not satisfy this requirement sufficiently.
For semiconductor device packaging suitable for insertion into sockets, there is the LCC (Leadless Chip Carrier) which has a body made of ceramic, and which makes external connections by means of metal printed as terminals on sides of the body, but it requires extremely high packaging cost.